Georges is recently returned from the French army in Algeria and has come to Paris to better himself. Down to his last few francs, he bumps into Forestier, an older man whom he knew in Algeria. Forestier tells him that Paris is filled with money and opportunities; he brags that he is the Political Editor at La Vie Française, a newspaper poised to bring down the government. He invites Georges into his home for dinner.
The dinner is attended by the cream of Paris society. Forestier, his beautiful wife Madeleine and the newspaper's editor, Rousset, rail about the political situation in North Africa, where the government is planning to enter Morocco. Madeleine says that the newspaper should publish Georges’s diary of a young soldier. She offers to help Georges but in fact writes the romantic account herself. She suggests that Georges should call upon two of her friends: the demure Madame Rousset and the sweetly flirtatious Clotilde. She advises him that the most important people in Paris are not the men but their wives. Madeleine sends Georges away when the elderly Comte de Vaudrec arrives for his weekly visit.
At La Vie Française, Georges finds that the diary has been a success and Rousset puts him on the payroll. Georges pays a visit to Clotilde. Her young daughter warms to Georges and calls him "Bel Ami", a name that sticks with the society ladies. Georges and Clotilde start an illicit affair but after enjoying a lot of fun together, she breaks it off.
Georges feels that his luck has run out. Forestier has run out of patience with the young man. He can't write without Madeleine's help and, even though colleagues murmur that Forestier's wife writes everything for him, Forestier fires Georges. Georges finally sees a reason to visit Madame Rousset, his former editor's wife. She is easily charmed by him and he finds himself re-employed at the newspaper as Head of Gossip.
Now back in society circles, he is reunited with Clotilde, who tells him that Forestier is dying and that Madeleine has taken him to the coast. Georges senses another opportunity and follows them. He stays by Madeleine's side until her husband is dead and buried.
Georges marries Madeleine. Now that Madeleine is writing for him again, Georges is promoted to Political Editor. Madeleine throws herself into the work and the stories that Georges submits play a pivotal role in overthrowing the government. Rousset throws a lavish party to celebrate what he sees as his political victory. When Georges tries to claim his part in this coup, Rousset goads him - he tells Georges that Madeleine is completely under the control of the Comte de Vaudrec.
Sensing that she is attracted to him, and to get back at his boss, Georges sets his sights on Madame Rousset. She is easy prey to him and he seduces her whilst she is at prayer in church. They start an affair whilst Georges simultaneously continues his love affair with Clotilde.
The Comte de Vaudrec dies and bequeaths his fortune to Madeleine. Georges’s suspicions about the intimacy of their relationship are confirmed and humiliated, he turns on her. Grief stricken, Madeleine admits that the man had been everything to her: friend, father and lover.
Madame Rousset has become infatuated with Georges. Disgusted by her, Georges spurns her advances, so she tries to win him back by revealing that the new government is now going to invade Morocco. Her husband knows all about it and what's more has been exploiting the situation in order to make his fortune. Georges brutally ends their affair and angrily confronts Rousset and Madeleine, who he imagines was also involved. They both turn the tables on Georges, casting him out of their lives.
Georges turns up uninvited to Rousset's party where he is snubbed by everyone, including Madeleine. Only Clotilde is welcoming. They talk and Georges accepts that he has behaved like a fool. Back at the party, Rousset and his wife are presenting their teenage daughter, Suzanne who smiles at "Bel Ami".
Georges takes the police with him to confront Madeleine and her new lover. She willingly confesses to the crime of adultery. Now free again, Georges runs away with Suzanne. When her parents catch up with them, Rousset insists that Georges must marry Suzanne to save her character, in spite of her humiliated mother's protestations. When Clotilde finds out what he has done, she berates Georges for his cruelty. His defence is that he must do whatever it takes to fight his way out of poverty.
Georges marries Suzanne in a grand ceremony. As the couple walk down the aisle, Georges sweeps past the women he has used and abused to attain his final goal: Madame Rousset, Madeleine and Clotilde, his one true love....more